Note that it appears that FileHash has not changed across versions. The following hash function will produce the same results in v7 and v8, although those results will not be the same as what you get from Hash in either version:

I believe you have the reason, but the proposed function does not give output that matches the v8 Hash function. Did you test it?
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Mr.Wizard♦Oct 23 '12 at 17:24

The point of myHash is that it will return the same results in v7 and v8. However, these results will be different than the results from Hash - it is not intended to reproduce the result of the v8 Hash in v7 (it looks VLC has a more clever approach). I will edit my response to make this more clear.
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KAIOct 23 '12 at 17:30

+1 -- incidentally I tried a Trace[. . . , TraceInternal->True] on Hash and it seems to already be using Java. It's also almost comical how complicated it appears to be.
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Mr.Wizard♦Oct 23 '12 at 18:07

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